Subsea installations used in the oil and gas industry are often inter-connected by umbilicals, jumpers and other tubulars, which provide a conduit for electrical power, communications, hydraulic power and fluids between the various subsea installations. Conventionally, cables and tubulars have been installed from a reel located on a pipeline laying vessel on the surface of the sea. A remotely operated vehicle (ROV) typically carries each end of the jumper and flies it into position. If a jumper is installed onto a reel, bends are imposed on the jumper. When the jumper is unwound from the reel for deployment on the seabed, the jumper can kink and this can compromise the integrity of the jumper if the removal of the jumper from the reel during deployment is not properly controlled.
Furthermore, the jumper is required to be tensioned in order to maintain the jumper on the reel and avoid the coil diameter from expanding due to the energy stored in the coil. This can be achieved by simultaneously applying a braking force to the unravelling coil at the reel and engaging part of the jumper as it leaves the reel with rollers to impose a tension on the jumper and retain the jumper in its coiled condition. For subsea applications, the jumper is typically manufactured from steel and is relatively stiff. As a result, the forces that must be applied to maintain the jumper in tension can be considerable and could result in crushing of the jumper at the point where the rollers are gripping.
Jumpers can be deployed from a basket of a storage frame, without the need to apply this tension. However, towing the jumper over long distances places high demands on the ROV, which results in a maximum possible length of jumper of around 150 metres. If longer conduits are required between the subsea installations, one or more in-field umbilicals must be deployed from a vessel with each end of the umbilical positioned close to the required position adjacent the installation. The ends of the umbilicals can then be linked to the subsea installations using shorter jumpers to connect umbilical end terminations with the subsea installations. Thus, deployment of in-field umbilicals can be expensive and time consuming.